sixpenceee:Shakuntala Devi, an Indian mental calculator,was asked to give the 23rd root of a 201-dig
sixpenceee:Shakuntala Devi, an Indian mental calculator,was asked to give the 23rd root of a 201-digit number; she answered in 50 seconds. Her answer was confirmed by calculations done at the US Bureau of Standards for which a special program had to be written to perform such a large calculation. -- source link